A common weapon used against armored targets is the Semi-Active Command to Line of Sight Anti-Tank Guided Missile (SACLOS ATGM). These missile systems guide a missile to follow the line of sight (LOS) between a guidance set of the missile system and the target. The missile system operator establishes the LOS via a direct view optical sight or imaging sight, and the guidance set estimates the offset of the missile from the LOS by measuring the angle between the LOS to the target and the LOS to the missile. Because it makes an angle measurement, the guidance set is also called a goniometer. To find the LOS to the missile, the guidance set relies on detecting and tracking a beacon located at the missile. The guidance set generates commands to the missile to keep it heading toward the goniometer's aimpoint. The commands and related information are passed to the missile via a trailing wire, by radio frequency transmission, or other means. Typically the field of view (FOV) of the goniometer is wide at missile launch, just long enough to detect and “capture” the missile beacon. The radiant intensity of the missile beacon must be large enough for the goniometer to detect it in the presence of background clutter and other noise sources. Detection may be aided by limiting the spectral band-pass of the goniometer to optimize contrast with background noise. Commonly used spectral bands may be in the near infrared region and are determined by detector materials used. After the missile beacon is captured, the FOV of the goniometer rapidly changes to a narrow FOV to bring the missile to the LOS and, ultimately, the target. Typically, this narrowing of the FOV is completed within a few seconds of launch. Such missiles can effectively disable or destroy targets, such as armored vehicles.